Struct Extensions

pub struct Extensions { /* private fields */ }

A type map for request extensions.

All entries into this map must be owned types (or static references).

Implementations

impl Extensions

pub fn new() -> Extensions

Creates an empty Extensions.

pub fn insert<T>(&mut self, val: T) -> Option<T>

where T: 'static,

Insert an item into the map.

If an item of this type was already stored, it will be replaced and returned.

let mut map = Extensions::new();
assert_eq!(map.insert(""), None);
assert_eq!(map.insert(1u32), None);
assert_eq!(map.insert(2u32), Some(1u32));
assert_eq!(*map.get::<u32>().unwrap(), 2u32);

pub fn contains<T>(&self) -> bool

where T: 'static,

Check if map contains an item of a given type.

let mut map = Extensions::new();
assert!(!map.contains::<u32>());

assert_eq!(map.insert(1u32), None);
assert!(map.contains::<u32>());

pub fn get<T>(&self) -> Option<&T>

where T: 'static,

Get a reference to an item of a given type.

let mut map = Extensions::new();
map.insert(1u32);
assert_eq!(map.get::<u32>(), Some(&1u32));

pub fn get_mut<T>(&mut self) -> Option<&mut T>

where T: 'static,

Get a mutable reference to an item of a given type.

let mut map = Extensions::new();
map.insert(1u32);
assert_eq!(map.get_mut::<u32>(), Some(&mut 1u32));

pub fn get_or_insert<T>(&mut self, value: T) -> &mut T

where T: 'static,

Inserts the given value into the extensions if it is not present, then returns a reference to the value in the extensions.

let mut map = Extensions::new();
assert_eq!(map.get::<Vec<u32>>(), None);

map.get_or_insert(Vec::<u32>::new()).push(1);
assert_eq!(map.get::<Vec<u32>>(), Some(&vec![1]));

map.get_or_insert(Vec::<u32>::new()).push(2);
assert_eq!(map.get::<Vec<u32>>(), Some(&vec![1,2]));

pub fn get_or_insert_with<T, F>(&mut self, default: F) -> &mut T

where T: 'static, F: FnOnce() -> T,

Inserts a value computed from f into the extensions if the given value is not present, then returns a reference to the value in the extensions.

let mut map = Extensions::new();
assert_eq!(map.get::<Vec<u32>>(), None);

map.get_or_insert_with(Vec::<u32>::new).push(1);
assert_eq!(map.get::<Vec<u32>>(), Some(&vec![1]));

map.get_or_insert_with(Vec::<u32>::new).push(2);
assert_eq!(map.get::<Vec<u32>>(), Some(&vec![1,2]));

pub fn remove<T>(&mut self) -> Option<T>

where T: 'static,

Remove an item from the map of a given type.

If an item of this type was already stored, it will be returned.

let mut map = Extensions::new();

map.insert(1u32);
assert_eq!(map.get::<u32>(), Some(&1u32));

assert_eq!(map.remove::<u32>(), Some(1u32));
assert!(!map.contains::<u32>());

pub fn clear(&mut self)

Clear the Extensions of all inserted extensions.

let mut map = Extensions::new();

map.insert(1u32);
assert!(map.contains::<u32>());

map.clear();
assert!(!map.contains::<u32>());

pub fn extend(&mut self, other: Extensions)

Extends self with the items from another Extensions.

Trait Implementations

impl Debug for Extensions

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Extensions

fn default() -> Extensions

Returns the “default value” for a type.